Essential oils are not essential to anything, the word means essence
Calling clove or lavender oil essential says nothing about health. The term refers to essence: the volatile compounds that carry a plant's scent. The world makes an estimated 100,000 tons of them a year, and they turn up in perfume, food, pest control and hospital aromatherapy, not always harmlessly.
Chemically, essential oils are mixtures of water-repelling organic compounds that evaporate easily, locked inside rinds, leaves and bark until the plant is crushed or steamed. The international standard recognises three ways to make them: steam distillation, cold-pressing the peel of citrus fruit, and various solvent extractions. One plant can yield several kinds; the bitter orange is an example.
Pest control is one of the more promising uses. Oils from rose, lavender, thyme, peppermint, eucalyptus and others deter insects in studies, putting them off feeding, slowing growth or cutting reproduction, while the active molecules are generally harmless to mammals. Some perform as well as DEET against mosquitoes, but only while they are evaporating, so formulators blend them into creams and polymers to stretch that window. By 2012 the European Union had approved several, such as tea tree oil as a fungicide and citronella as a herbicide.
Food is a harder sell. The US Food and Drug Administration granted many oils GRAS status, meaning generally recognised as safe, during the 20th century, and compounds such as thymol and carvacrol kill microbes in the lab. Yet real foods need far higher doses than laboratory broth, because fat content, thickness and storage times differ, so they are rarely used as preservatives.
In care settings, aromatherapy is used for relaxation, including by people with nausea and pain from cancer treatment, and may ease anxiety, stress or insomnia in palliative care. The oils can also do harm. Tea tree oil commonly causes contact dermatitis, swallowing oils can be dangerous, particularly for children, and balsam of Peru ranks among the five allergens most often behind positive skin patch tests at dermatology clinics.
Source: Essential oil
